1. Field of the Invention
The present invention relates to a relay communication system including a plurality of relay servers that can communicate with each other, a plurality of client terminals, and LANs connecting the client terminal to the relay server, and also relates to a relay server used in the relay communication system.
2. Description of the Related Art
In some systems, client terminals connected to remote local area networks (LANs) communicate with each other through a wide area network (WAN). A virtual private network (VPN) makes it possible to configure a virtual network in which the remote local area networks (LANs) are connected directly with each other. However, in the virtual private network (VPN), it is difficult to configure a network that is expandable and flexible.
A relay communication system shown in Japanese Laid-open Patent Publication No. 2008-129991 can configure a virtual network in which the remote local area networks (LANs) are directly connected with each other, as in the virtual private network (VPN). Moreover, in the relay communication system, it is easy to configure a network with expandability and flexibility, unlike the virtual private network (VPN).
In the relay communication system shown in Japanese Laid-open Patent Publication No. 2008-129991, the number and the connection states of LANs and client terminals may be changed. However, in Japanese Laid-open Patent Publication No. 2008-129991, no specific means is disclosed that confirms changes to the number of client terminals and connection states of client terminals in real time when the relay server designates a destination for communication. In Japanese Laid-open Patent Publication No. 2008-129991, no specific means is disclosed to dynamically configure a virtual network between a client terminal and a relay server.